by Rida Fatima
(Fig 1: Illustration of a photobioreactor that could grow food and building materials on Mars. Credit: Joris Wegner/ZARM/Universität Bremen.)
Bacteria can contribute to the formation of materials on Mars by a process known as biomineralization. Biomineralization is the process by which microorganisms produce and incorporate minerals into their structures and the surrounding environment. This process can create a variety of different materials, such as calcium carbonate, silica, and iron oxides, which can eventually become fossils that can be analyzed for evidence of past life. In the case of Mars, it is possible that microorganisms could have biomineralized in the past, forming structures such as stromatolites or other fossil-like structures that could serve as evidence of past life. Additionally, bacteria could be used to support human exploration of Mars by producing resources such as oxygen, food, and building materials. For example, certain species of bacteria could be used to extract minerals from Martian soil and process them into usable building materials, such as bricks or concrete (Gohd, 2023).
However, it is important to note that biomineralization on Mars would be a complex process that would require careful consideration of the harsh Martian environment, including factors such as low atmospheric pressure, intense radiation, and the lack of water. In addition, any bacterial populations that are established on Mars would need to be carefully managed to ensure that they do not contaminate the Martian environment and interfere with future scientific studies of the planet.
Biomineralization on Mars
Biomineralization refers to the process by which living organisms produce minerals and incorporate them into their bodies or external structures. On Mars, biomineralization could have taken place in the past if the planet once had conditions suitable for life. Evidence of biomineralization on Mars could help scientists to understand the nature and extent of past life on the planet, as well as the geochemical processes that took place on its surface. The presence of biomineralization on Mars could be indicated by the detection of minerals such as carbonates, silicates, and sulfates, which are commonly associated with biotic processes. Scientists are also searching for evidence of fossilized microorganisms, such as stromatolites, that could provide insight into the history of life on Mars. To search for biomineralization on Mars, scientists are using a variety of techniques, including X-ray diffraction, spectroscopy, and imaging (Tomaswick, 2023). The Mars rovers, Curiosity and Perseverance, are equipped with instruments that can analyze Martian rocks and soils to determine their mineral content and search for evidence of past life.
NASA Innovative Advanced Concepts (NIAC) for Phase I development
Jin — an assistant professor of civil and environmental engineering at the University of Nebraska, Lincoln, recently spoke with Universe Today via Zoom and described the path that led to her NIAC proposal,
“I have been working on self-healing concrete for the past few years. Therefore, we use bacteria or fungi to stimulate the biominerals to mend cracks when concrete develops them. Next, we consider alternative options like self-growing materials. So one would have aggregates or soil particles. To create a coherent body, we wish to use fungi or bacteria. We can just ship some bacteria or fungal spores to Mars in order to collect samples of the soil, atmosphere, and water, and they will construct the bricks for us”
The process of “biomineralization,” in which bacteria and spores can put together minerals like calcium carbonate (CaCO3), or limestone, is the key to this. Since the Pheonix Mars Lander discovered evidence of CaCO3 at its landing location in 2008, scientists have known that Mars contains limestone and other carbonates. Later sample analysis by the Spirit and Opportunity rovers and mineral mapping by missions like NASA’s Mars Reconnaissance Orbiter supported this (MRO). If there is no human labour, especially on Mars, this will be highly crucial. They can carry it out automatically. We suggest using materials already present on Mars rather than transporting them there.
Future missions might be provided with “synthetic biological toolkits,” in Jin’s idea, to produce synthetic lichen systems (diazotrophic cyanobacteria and filamentous fungi). When coupled with Martian regolith, they will transform CaO3 into a plentiful source of biopolymers that can be used to “create” building materials. According to Jin, “They will act as a catalyst to encourage the development of calcium carbonate, and those calcium carbonate crystals will act as a glue to bond those soil particles together.” The sand particles must be placed into the desired mould for the bacteria and fungi to develop and take on the shape of the mould.
The filamentous fungus and cyanobacteria each have a unique role to play in this envisioned autonomous system. The cyanobacteria, according to the NIAC concept, are in charge of the following:
1) absorbing carbon dioxide and converting it to carbonate ions and
2) supplying oxygen and organic chemicals to support the filamentous fungi.
However, the fungi are in charge of two important functions:
1) binding calcium ions to the cell walls of the fungi and acting as nucleation sites for calcium carbonate deposition.
2) promoting the survival and expansion of cyanobacteria by increasing their carbon dioxide levels and lowering their oxidative stress.
Additionally, the cyanobacteria and fungi release “Extracellular Polymeric Compounds” that improve the cohesiveness of precipitated particles as well as the adhesion of regolith particles to biopolymers. In order to ensure that these artificial bacteria and fungi function symbiotically rather than competitively, Dr. Jin also described the procedure for manufacturing them:
“We must identify the strains that get along well with one another. Mutualistic co-culturing is the name for it. In essence, some of them can improve the partner’s quality of life. Because of their filamentous structure, we require filamentous fungus. They can encourage more calcium carbonate crystals to form. However, we also require cyanobacteria, which can perform photosynthesis and produce organic carbon for fungus in the process of absorbing CO2.”
Bioreactors Produce Self-Healing Bricks
The proposal envisions bioreactors producing bricks that are removed to build surface structures. These building materials will also be self-healing, Jin says. “They have a lot of features that we don’t have with materials on Earth,” she said about Martian materials. Despite the fact that biomineralization is a topic that has been studied for years, this idea is unique for two reasons. It is the first effort, for one thing, to explore filamentous fungi as a source of biominerals rather than bacteria. Jin has studied biomineralization extensively recently, and her findings have shown that filamentous fungi have different benefits over bacteria. The most notable of these is their amazing ability to create a lot of minerals quickly (Tomaswick, 2023).
Second, by developing a synthetic lichen system and utilising symbiotic interactions between photoautotrophic cyanobacteria and heterotrophic filamentous fungi, this study is the first to use self-growing technology. It is well known that photoautotrophs use sunshine to convert inorganic carbon into organic molecules (in this case, organic carbon). Since they were typically limited to a particular species or strain of heterotrophs reliant on an ongoing external supply of organic carbon, none of the self-growing techniques examined thus far have been totally autonomous.
The technology has the potential to transform construction here on Earth in addition to creating habitats on Mars and other planets beyond Earth. This autonomous, self-growing technology has the ability to “repair” damaged structures and create new infrastructure while leaving a small carbon imprint in areas that have been impacted by conflict, natural catastrophes, and climate change. This technology is another illustration of how biological systems and species from the Earth inspire resilient and sustainable space systems. The same technologies that might make it possible for humans to live sustainably in space might also assist us in halting and reversing climate change on Earth. The interaction is symbiotic, much like the process that drives this suggested bioreactor technology (Tomaswick, 2023).
- Gohd, Chelsea. “Building a Home on Mars” With Bacteria?” Space.com, 22 Apr. 2022, www.space.com/building-mars-habitat-with-bacteria.
- Tomaswick, Ady. “Bacteria Could Help Form Building Materials on Mars.” Inverse, 29 Jan. 2023, www.inverse.com/science/nasa-niac-bacteria-on-mars.